Shingle-drying kiln



Patented dan. 13,1925.

`PATE-NT' A OFFICE.

NATHANIELWMQNMR, YorI vertoonvan,v I:aereas,1g-,r COLUMBIA, CANADA.

sHINGLE-DRYING Kinn.

Appncation med June 1e, 192s; serial No. 645,152.

To all whom t may concern.'

Beit knownthat I, NafuraNinn MCNAIR, citizen of the Dominion'of Canada, residing `at Vancouver, in the Province of British Columbia, Canada, have invented certain newand `useful Improvements in Shingle- Drying Kilns, oifwhich the following is a specifica-tion.A f f This invention relates to an improvement in shingle drying kilns, the improvements `being"directed `tothe nabstraction of the moisture laden air from the kiln 'ata relatively low temperature whereby a more uniform heat is maintained throughoutthe stacks of shingles being dried, whereby the shingles are more quickly and thoroughly dried and with ai greater economy of heat.

These results are attained by a careful 'consideration of -thelconditions prevailing in shingle drying kilnsA as at present constructed In `the present `practice the? bundles uof cut-shingles are'loosely stacked on trucks, which are runinto a substantially air-tight?chamberrheated by steam pipes horizontally disposed immediately 4below the level ofjthe `track rails whereby-the heated lair 'rising fromj the steam pipes 'passes through the bundles of stacked shingles and evaporates the moisture from them.

` IlVhileV it is admittedly desirable -to withdraw this moisture laden air romthe chamber,"grea`t diversity of 'opinion exists as to what part of the chamber-it should be drawn from. Generalopinion favours withdrawing `it from the upper part, 'which is now usually done by providing a series 'of ducts inthe side walls of the chamber adjacent one end and at approximately half the height of the chamber, which ducts are `connected to an uptake or chimney at one' end, and air inlet-ducts are provided inthe lower part of the chamber at the opposite end. l

While thispractice'is, to a certain extent, satisfactory, the moisture laden Aair being :withdrawn'from thel upper part oit the chamber carries to waste a considerable amount ofheat having further evaporative capacity.A It alsof limitsthelevelof relativelyhightemperature in the kiln chamber to above the-exit aperture, as the moisture laden air falling down the sides ofthe chamber h'as,`below the level of the `withdrawal ducts, a temperature considerably 'lower `than 'that above the ducts, v1"*lhis moisture ,readily `which are relatively lcooler than'the moisture laden air, and this condensed moisture has `later to be re-evaporated from the shingles.

This conditioniis evidenced in the fact that yin Jthe customaryV kilns the lower bundles of shingles are invariably much discoloured and the iron clasping bandsu are rusted; also in the, fact that at thecompletion of the drying process the weight of the shingles from the `lower part of the stack is considerably greater than those from'the upper part of the same. y

'I hese defects I have overcome in the "kiln, which is the subject of this application., by withdrawing the moisture laden air not from the upper part of the chamber, but i' rom the lower part of the same, that is, from below the level of the steam heating pipes. The withdrawal ductsl have a considerably greater area-than what is atpresent used, say

As this moisture laden air cools it descends the sides of the chamber and may again circulate upward past the steam pipes and the shingles but such of it as is fullyf saturated with moisture being cooler and heavier, will pass below the steam pipes to the bottom of the chamber and is withdrawn at the further end.` l

The admission being at one end and the withdrawal at ther other" end causes a progressiveflow through "the "chamber during its ascent through the shingles, `while hot, and its descent down the sides ofthe chamber as it cools. y'

By' thisl means the temperature of th chamber is maintained l reasonably uniform throughout the depthvofthel stacks of the shingle bundles and no l air is "withdrawn that has possibilities `of further evapora!- tion. `This` s evidenfl @he fact that the Eil ' 30 outthe length of the kiln. v

shingles are more fully dried in the same time andto a substantially uniform extent, and they are free from moisture discolouration and rust.

The invention is particularly described in the following specification, reference being made to the drawings by which it is accompanied, in which:

Fig. 1 is a longitudinal section of the kiln.

Fig. 2 is a sectional plan of the same, and

Fig. 3 is a cross section on the line 343 in Fig. Zlooking in the direction of the arrow, `showing the charge of shingle bundles.

In these drawings 2 represents the side walls of the roofed kiln, 3 being Vthedoors closing air-tight the entrance to the kiln, and 4 those closing'the exit. Throughout the length of this kiln, track rails 5 are supported at an approximate height of five or six feet from the bottom of it, and beneath these track rails a series of steam pipes 6 are carried lengthwise of the kiln from a transverse delivery header 7 to a transverse dis-- charge header 8, the pipes 6 being at a slight downward slope toward the discharge header 8 with a quick fall immediately adjacent the vconnection thereto, by Vwhich means the heating pipes 6 are maintained in close proximity to the shingle pack through- At the floor level, and therefore below the heating pipes 6 are apertures 10 beneath the exit. doors 4, through which apertures air is admitted yto within the chamber, which admission is controlled by dampers 11.

Across the opposite or entrance end of the kiln ample exit apertures 12 deliver into a transverse duct 13 and therefrom into two .uptakes 14 for the delivery of moisture laden air from the chamber under naturalV draught.y These uptakes 14 are not only larger in area than is customary but are higher as the vapours conducted by them are relatively cooler than usual.

The bundles of shingles are, as at present, stacked loosely on low wheeled trucks 15, and are run into the chamber on the track rails 5 and with all doors closed air-tight, the air heated from the steam pipes 6 passes upward through the interspaces of the stacked` shingle bundles and evaporates the moisture therefrom. This moisture-laden air rises to the top of the chamber and as it cools or is displaced by other rising moisture laden air it `passes by-convexion 4down the side walls. Q'of the kiln where it may againbe heated by contact with the steam pipes 6 and evaporate more moisture from the shingles, but the fully saturated and cooler air will reach the lower part of the chamber below the steam pipes 6 and find lits exit throu'ghthe ducts 12 and transverse duct 13to the uptakes 14.

The result is certainly advantageous, as a considerably higher temperature is, 1.10.3111* tained throughout the entire depth of the charge of shingles being dried, and evidence of any'condensation ofn'ioisture on the lower shingles of Vthe stack, which is very marked in the output of the usual shingle drying kiln, isv entirelyl absent.n The sh1n gles lare more completely dried for the same period of exposure, and the drying` is more uniform throughout the depth of the stack.

I am aware that prior to my invention at# tempts have been madeto withdraw the moisture laden air from the lower part of the kiln, but in all with which I amacfquainted,v the replacement air has been' admitted above the steam pipes to the upper part ofthe chamber and has been ineffective. Never within my knowledge hasthe air been admitted to a shingledrying kiln belowgthe heating pipes at or near thebottom atV one end and withdrawn, 'when' saturated with moisture, from approximately'thesame level at or adjacent the other end. i

' be the Obviously. the air withdrawnmust coolest and be moisture laden.

, I-Iaving now particularly described chamber for admitting below the heating,

means external air forl replacement.

2. A drvlng kiln forV shingles, comprising i the combination' with a substantially airtight chamber having` steam heating pipes disposed along the lengthandbreadthfof the chamber at -a short distanceY from the bottom thereof, withdrawalductsat one end of the chamber below' the level of thesteam heating pipes,` said ducts communicating with an uptake, and ducts admitting external air Yto the chamber below thelevel Aofthe heating pipes. i 3'. a

3. drying kiln for shinglescomprising the combination with' a substantially air-- ,tight chamber having steam heating pipes disposed along the length andbreadth of the i chamber at a short distance from the bottom thereof, withdrawal ducts atone end ofthe chamber below the level ofthe steam heat,-v mg pipes, said ducts Vcommunicatingi'with `an uptake, and ducts admittingl external air to the chamber below the level of the heating pipes and remote from the withdrawal ducts, andl means for controlling the amount of'air admitted. a

f4. A drying kiln'for shingles-comprising the combination with a substantially airn 1,522,960 i S3 tight chamber having steam heating pipes disposed along the length and breadth of the chamber at a short distance from the bottom thereof, Withdrawal ducts at one end of the chamber and substantially at the level of the bottom thereof, said ducts communicating with an uptake, and ducts at the op posite end of the chamber admitting external air to the chamber below the level of the heating pipes, and means for controlling the 10 amount of air admitted.

ln testimony whereof I aix my signature.

N ATHANIEL MGNAIR. 

